Treatment of hydrocarbon oils



Patented Jan. 28, 1936 UNITED STATES PATENT OFFICE TREATMENT OFHYDROCARBON OILS No Drawing. Application December 14, 1931, Serial No.581,022

4 Claims.

This invention relates to the treatment of hydrocarbon oils and refersmore particularly to the treatment of the lighter distillates producedin the cracking of heavier oils although similar distillates producedfrom the primary or noncracking distillation of crude petroleums mayalso be treated.

More specifically the invention relates to the treatment of suchhydrocarbon mixtures While in a heated vaporous condition, a processbeing disclosed which accomplishes the necessary refining of such vaporsprior to their condensation and substantially eliminates the necessityfor extensive treatment of the distillates and their subsequentrerunning, thus effecting much needed economies.

It has been recognized for some time by those engaged in the petroleumindustry that the usual method of treating cracked distillates withsulphuric acid followed by neutralization and rerunning to produce endpoint gasoline possesses numerous inherent disadvantages due principallyto the need for special auxiliary treating equipment and the necessityfor rerunning the treated distillates. Even though distillates ofgasoline end point are treated, rerunning is usually necessary onaccount of the formation of high boiling polymers, sulphuric acidderivatives, sulfoxy compounds, etc. which raise the final boiling pointof the gasoline. Of the proposed vapor phase treating methods thus fartried a few have attained commercial status, notably treatments Withsolid adsorbents such as fullers earth. As yet, however, it cannot besaid that any one type of vapor phase treatment has been found which isefiicient enough to completely supersede the customary acid treating andrerunning of cracked distillates. The present invention provides animprovement over existing commercial processes which possesses markedadvantages over those now in vogue, the details of the present inventionbeing set forth in the following paragraphs.

In one specific embodiment the invention comprises the treatment ofhydrocarbon vapors, particularly cracked hydrocarbon oil vapors, withliquid sulphuric acid solutions of various concentration containingsubstantially neutral organic compounds or the reaction products betweenthese compounds and sulphuric acid.

It will be evident from the preceding paragraph expressing the preferredembodiment of the invention that it comprises essentially a modificationof the idea of using dilute aqueous sulphuric acid, the range of use ofthe latter being very limited due to the fact that under the conditionsof temperature and pressure common to fractionators which are handlingcracked vapors that any dilute aqueous sulphuric acid which may be addedthereto is rapidly concentrated to a strength which is undesirablebecause of its pow- 5 erful oxidizing and charring effect, producingthus cokey sludges and too severe an effect upon the vapors. The use ofspacing agents of the types mentioned in the preceding paragraph enablesthe use of sulphuric acid in a sufficiently 1O diluted condition forefiicient vapor phase treatments since the vapor pressure of suchcompounds, properly selected with regard to their physical and chemicalproperties, may be considerably lower than that of water so that thetendency to change the composition of the solution due to evaporation ofthe solvent is lessened.

The invention contemplates the use of sulfonic acids of compounds of asubstantially neutral nature or at most only slightly acid or alkaline.For example, it includes the use of sulfonic acid of benzol and itshomologs and also the sulfonic acids of multi-ring compounds such asnaphthalene, anthracene, phenanthrene, etc. when the sulfonic acids ofthese compounds are of proper chemical and physical characteristics. Theinvention further contemplates the use of sulfonic acids of the chlor,nitro and hydroxyl derivatives of the aromatic or ring hydrocarbonsmentioned. For example, diluting or spacing reagents may be made bysulfonating monochlorbenzol, mononitrobenzol, or phenol.Poly-substituted compounds and mixed substitution compounds may also beemployed as bases for the manufacture of sulfonic acids. For example,metadichlor benzol may be sulfonated, or paradinitrobenzol or resorcinolmay be used. Compounds similar to cresols and other phenols of homologsof benzol may also be used as starting materials when their sulfonicacids have the right properties. Suitable compounds for use as diluentor spacing agents may be formed by reacting upon unsaturated chaincompounds with 4D sulfuric acid, the product of these reactions beingcompounds of the type of mono or dialkyl sulfates. The particularolefins available for the manufacture of such compounds will in generalbe those which do not suffer extensive polymeri- 5O zation such as themono olefins corresponding to the normal parafiins.

Another class of compounds which may be utilized and which may or maynot undergo sulfonation during their use are the aldehydes and ketonesof ring compounds such as, for example, benzaldehyde, diphenyl ketone,etc.

From the statements just made concerning the types of compounds whichmay be employed as diluting or spacing materials it will be evident thata large number of reagent treating solutions of varying composition maybe made up to suit the needs of difierent treatments. While in mostcases the virtue of the treating solution employed is due principally tothe sulfuric acid, it is recognized that the organic compounds used asspacing agents may at times exert a definite chemical influence upon thereactions other than merely moderating the effect of the sulfuric acid.It will also be evident that the selection of any particular compound ormixture of compounds for use with the sulphuric acid will be determinedby solubility relations, the extent of refining treatment necessary uponthe vapors, the general operating conditions and the matter of economyin the cost of the reagents. However, such problems will be solved bythose familiar with the treating art without great difficulty.

The process may be conducted in any type of apparatus suitable forefficiently contacting vapors with liquid treating reagents. A filledtower containing crushed rock, fragments of porcelain, Raschig rings ormetallic filler is readily utilizable, the scheme of operation in such acase being to pass the vapors upwardly through the tower countercurrentto the descending treating solution which has been introduced above thebafiiing material through distributing means to assist in securingintimate contact of oil vapors and liquid. At other times greateradvantage may be gained by passing the vapors downwardly along with thetreating solution, this serving in some instances to allow betterseparation and disposition of sludge and heavy reaction products.Treatments of high efiiciency may be obtained by utilizing towers of thespaced-tray type, the trays being perforated or supporting bubble capssuch as are commonly employed in fractionating towers in the oilindustry. Towers may be lined with lead W fi, with ammonia or alkalisolutions to neutralize or other materials to minimize corrosion effectsor suitably chosen corrosion resisting metals may be employed in theirconstruction.

Another type of operation which may be successfully employed involvesthe simple expedient of merely allowing the vapors to rise through apool of treating solution, the solution being circulated to insurethorough mixing and used until substantially spent, at which time thevapors undergoing treatment may be diverted to a fresh sup-ply ofreagent in parallel connected towers, thus insuring substantiallycontinuous operation. Owing to the possibility of varying thecomposition of the treating solutions over a wide range, the process isadaptable for use under practically all conditions of temperature andpressure encountered in cracking, primary distilling or rerunningoperations upon Vapors containing large amounts of gasoline boilingrange fractions. The

.superatmospheric to high superatmospheric such as for example pressuresin the neighborhood of 300 lbs. per sq. in. or higher.

Treatments may be employed alone or in combination with other types ofvapor phase treat- For example, the vapors may be treated and removehydrogen sulfide, after which the process of the invention is appliedand vapors after the treatment may be further neutralized, subjected tofiltering or sedimentation to remove entrained particles or furtherneutralized and filtered to remove substantially all acidic reactionproducts. While it is contemplated that the process of the invention isin generalsufiicient to produce finished gasoline from cracked vapors inone step it may be at times necessary to subject the condensed gasolineto a mild neutralizing action which is easily accomplished by injectingminor amounts of caustic soda into the rundown line to storage.

The vapors treated may receive sufficient fractionation during thetreatment depending upon the type and capacity of treating toweremployed or they may be subsequently fractionated in separate equipment,with return of intermediate refluxes to the primary cracking stage forfurther conversion.

The sludges produced by the process of the invention will also vary incharacter depending upon the numerous factors entering into thetreatment and the steps necessary for their re-- covery for further usewill necessarily be modified accordingly. In most instances the generalprocedure commonly employed in recovering sludge from liquid phasesulfuric acid treatments is ap plicable, the sludge being diluted to aproper point with water to cause separation of oily material, and theaqueous solution being concentrated and receiving further addition ofchemicals to restore it to the proper composition for use. It iscontemplated to continuously regenerate used treating solutions as astep in the treating process.

Numerous examples of operation and the results obtainable therefrommight be given but a few will suffice to indicate the feasibility of theoperation from a commercial standpoint. As one example of operation, thegasoline range boiling vapors from a cracking process operating upon theMid-Continent residuum may be passed under pressure of approximately 50lbs. per sq. in.

counterflow to a descending solution containing approximately 45% ofsulfuric acid, 35% of benzene sulfonic acid and 20% of water. Thetemperature at the vapor exit at the top of the tower may be held atapproximately 345 F. and the vapors further passed in a downwardlydirection through a stationary filter bed consisting of a mixture offinely divided fullers earth and lime. The final fractionation of thetreated vapors may produce a gasoline suitable in all respects forcommercial use. The following tabulation of comparative properties of araw gasolineproduced without vapor phase treatment and that produced bythe refining operation just described will show the effect of thetreatment:

Raw Treated gasohne gasoline 54.3 413 +30 26 17 Sulfur 0. 35 0. 12

The continuous regeneration of treating solution from the sludgeproduced in the preceding example; and the circulation of reagentthrough the tower to enable its eflicient utilization may make possiblethe treatment to. the point shown in the tabulation by using as low as 5lbs. of reagent solution per bbl. of gasoline, which is well within therequired economy since the sulfonic acid is substantially unaffected inthe treating and regenerating steps and the only constituent needingreplenishment is the sulfuric acid.

As another example illustrative of the operation of the process asimilar operation to the one given may be conducted upon the vaporsproduced from cracking a California residuum. The reagent solutionemployed in this case may contain as the diluting or spacing compoundapproximately 39% of the sulfonic acid of mononitrophenol. By utilizingthe same general steps already outlined and an amount of reagentamounting to '7 lbs. per bbl. of finished gasoline improved re- Theforegoing specification and examples have sufliciently disclosed andillustrated the process of the invention and made its features andadvantages evident in comparison with existing processes, however, thebroad scope of the invention is not limited by the exact details of thespecification nor the particular examples given.

I claim as my invention:

1. In the refining of light petroleum distillates of the character ofgasoline, the step which comprises treating the distillate in vaporphase with a solution containing sufiicient sulphuric acid to eiiectsubstantial refining of the vapors and to which has been added asulfonated hydrocarbon in amount sufficient to dilute the sulphuric acidsubstantially.

2. In the refining of light petroleum distillates of the character ofgasoline, the step which comprises treating the distillate in vaporphase with a solution containing sufiicient sulphuric acid to eiiectsubstantial refining of the vapors and to which has been added asulfonated aromatic hydrocarbon in amount sufficient to dilute thesulphuric acid substantially.

3. In the refining of light petroleum distillates of the character ofgasoline, the step which comprises treating the distillate in vaporphase with a solution containing sufiicient sulphuric acid to effectsubstantial refining of the vapors and to which has been added asulfonated olefine hydrocarbon in amount suflicient to dilute thesulphuric acid substantially.

4. In the refining of light hydrocarbon distillates of the character ofgasoline, the step which comprises treating the distillate in vaporphase with a solution containing suificient sulphuric acid to effectsubstantial refining of the vapors and to which has been added benzenesulfonic acid in amount sufiicient to dilute the sulphuric acidsubstantially.

JACQUE C. MORRELL.

